The present invention relates to the formation of concrete curbs, and more particularly, to the formation of curbs adjacent driveways which normally interfere with their continuous preparation.
The conventional curb forming apparatus are devised with curb forming molds or "mules" which, during operation in producing curbs, are fixed for a job but may be moved vertically to some extent in conjunction with other equipment so that the mule will follow the contour of the road bed. When approaching a driveway, whether public or private, the host driving vehicle for the mule must be stopped, the pouring of concrete terminated, and the vehicle moved along to the other side of the driveway. A worker must be assigned the task of dressing the end of the curb so far produced as it joins the edge of the driveway.
This stop and repeat operation of the conventional curb forming apparatus is annoying, very time consuming and requires extra manpower to complete an average street. For an urban residential street wherein every house is provided with a driveway, considerable more funds are necessary to accomplish an acceptable performance of a curb forming operation.
In the prior art, such for example, as described in U.S. Pat. No. 3,797,958, a curb forming machine is disclosed as having a cut off plate which is moved horizontally with a mule so as to cut off the top portion of an extruded curb when moving across a driveway. However, this operation results in the accumulation of cut off curbing material upon the plate thereby necessitating the need of a workman to remove the material continuously from the plate during use. In addition, since the plate is cutting into the material, the resultant surface of the concrete curbing is unfinished, and the corners thereof will be roughened and irregular due to the occasional encountering of aggregate material. A different type of curb forming machine is described in U.S. Pat. No. 3,261,272 wherein a curb forming mold is adjustably supported. However, once this adjustment is made, it stays fixed. In view of the fact a reinforcing rod is included in a curb being formed, it would be impossible to effect stop and repeat operation needed when encountering driveways.
Other curb forming machines in the prior not endowed with provisions for the handling of driveways can be found in U.S. Pat. Nos. 3,733,140, 3,685,405, 3,820,913, 4,566,823, 4,391,549, 3,779,661, 3,954,359, and 4,310,293. In using the disclosed machines, the host driving apparatus for a curb forming mold must be stopped at each driveway encountered and special and time consuming effort must be expended thereat.
The present invention has been devised to overcome the difficulties and disadvantages discussed in the foregoing. To this end, an arrangement has been devised whereby a curb forming mule is adapted to be lowered gradually as the same approaches the oncoming edge of a driveway, this lowering working in conjunction with the movement of the driving vehicle which supports and drives the mule. As the mule lowers, the rear edge of the mule in contact the the top surface of the just molded curb gradually lowers therewith, thereby producing a downwardly tapering surface on plastic curbing material until the edge of the driveway is reached. This downwardly tapering surface may be a flat planar surface, or curved depending upon integrated movement between the driving vehicle and the descent of the forming edge on the mule. As the driving vehicle continues its non-stop movement across the driveway with the mule in its lowermost position, concrete continues to be extruded from the mule to produce a low profile threshold across the entrance to the driveway which separates the main portion of the driveway from the street. As the driving vehicle approaches the other edge of the driveway, the reverse process is set in motion wherein the mule is gradually raised so the rear forming edge produces an upwardly tapering surface on the concrete which continues to be extruded from the mule as the vehicle continues its movement along the street. When the mule has been raised to its initial curb forming position now having passed the driveway, the normal curb forming operation continues until the next driveway in the path of the driving vehicle is encountered.
From the foregoing, it will be understood that the present invention provides continuous operation of a curb forming machine as the same progresses along a street lined with driveways. As each driveway is encountered, the curb forming mold is lowered to form a descending end to the curbing while the mold continues in its path of movement. In traversing the driveway, a low profile threshold of the curbing material is cast in the plane of the driveway until the other edge of the driveway is reached, whereupon the curb forming mold is raised slowly in conjunction with the movement of the mold along the street whereupon the mold is adapted to effect the upward formation of the curb starting from the edge of the driveway. This lowering and raising of the curb forming mold, as the same is moved along the side of the street to accommodate driveways, is accomplished without interrupting the movement of the flow of concrete into the mold so that a continuous curb producing operation is available.
Therefore, the principal object of the present invention is to produce street curbing, without interruption, along a street having many driveways entering the street.
Another object of the invention is cast plastic concrete across driveways as a continuous operation in conjunction the formation of curbs.
Still another object of the invention is to produce curbing along a roadway formed with driveways therealong without interrupting the movement of the curb forming machine.
Still another object of the invention is to integrate the formation of curbs to the presence of driveways along the path of curb formation.
Other objects and advantages will become apparent after reviewing the following description taken in conjunction with the accompanying drawings wherein: